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Centers for Disease Control and
Prevention President’s Council on Physical Fitness and Sports |
The 1990s brought a historic new perspective to exercise, fitness, and physical activity by shifting the focus from intensive vigorous exercise to a broader range of health-enhancing physical activities. Research has demonstrated that virtually all individuals will benefit from regular physical activity.[1] A Surgeon General’s report on physical activity and health concluded that moderate physical activity can reduce substantially the risk of developing or dying from heart disease, diabetes, colon cancer, and high blood pressure.1 Physical activity also may protect against lower back pain and some forms of cancer (for example, breast cancer), but the evidence is not yet conclusive.[2], [3]
On average, physically active people outlive those who are inactive.[4], [5], [6], [7], [8] Regular physical activity also helps to maintain the functional independence of older adults and enhances the quality of life for people of all ages.[9], [10], [11]
The role of physical activity in preventing coronary heart disease (CHD) is of particular importance, given that CHD is the leading cause of death and disability in the United States. Physically inactive people are almost twice as likely to develop CHD as persons who engage in regular physical activity. The risk posed by physical inactivity is almost as high as several well-known CHD risk factors, such as cigarette smoking, high blood pressure, and high blood cholesterol. Physical inactivity, though, is more prevalent than any one of these other risk factors. People with other risk factors for CHD, such as obesity and high blood pressure, may particularly benefit from physical activity.
Regular physical activity is especially important for people who have joint or bone problems and has been shown to improve muscle function, cardiovascular function, and physical performance.[12] However, people with arthritis (20 percent of the adult population) are less active than those without arthritis.[13] People with osteoporosis, a chronic condition affecting more than 25 million people in the United States, may respond positively to regular physical activity, particularly weight-bearing activities, such as walking,[14] and especially when combined with appropriate drug therapy and calcium intake. Increased bone mineral density has been positively associated with aerobic fitness, body composition, and muscular strength.[15]
Although vigorous physical activity is recommended for improved cardiorespiratory fitness, increasing evidence suggests that moderate physical activity also can have significant health benefits, including a decreased risk of CHD. For people who are inactive, even small increases in physical activity are associated with measurable health benefits. In addition, moderate physical activity is more readily adopted and maintained than vigorous physical activity.[16] As research continues to illustrate the links between physical activity and selected health outcomes, people will be able to choose physical activity patterns optimally suited to individual preferences, health risks, and physiologic benefits.
For individuals who do not engage in any physical activity during their leisure time, taking the first step toward developing a pattern of regular physical activity is important. Unfortunately, few individuals engage in regular physical activity despite its documented benefits. Only about 23 percent of adults in the United States report regular, vigorous physical activity that involves large muscle groups in dynamic movement for 20 minutes or longer 3 or more days per week. Only 15 percent of adults report physical activity for 5 or more days per week for 30 minutes or longer, and another 40 percent do not participate in any regular physical activity.
Public education efforts need to address the specific barriers that inhibit the adoption and maintenance of physical activity by different population groups. Older adults, for example, need information about safe walking routes. Persons with foot problems need to learn about proper foot care and footwear in order to reach appropriate activity levels. People with CHD and other chronic conditions must understand the importance of regular physical activity to maintain physical function. Each person should recognize that starting out slowly with an activity that is enjoyable and gradually increasing the frequency and duration of the activity are central to the adoption and maintenance of physical activity behavior. Along with the public education efforts, public programs in a variety of settings (recreation centers, worksites, health care settings, and schools) need to be developed, evaluated, and shared as potential models. The availability of group activities in the community is important for many.
Disparities in levels of physical activity exist among population groups. The proportion of the population reporting no leisure-time physical activity is higher among women than men, higher among African Americans and Hispanics than whites, higher among older adults than younger adults, and higher among the less affluent than the more affluent. Participation in all types of physical activity declines strikingly as age or grade in school increases. In general, persons with lower levels of education and income are least active in their leisure time. Adults in North Central and Western States tend to be more active than those in the Northeastern and Southern States. People with disabilities and certain health conditions are less likely to engage in moderate or vigorous physical activity than are people without disabilities. Health promotion efforts need to identify barriers to physical activity faced by particular population groups and develop interventions that address these barriers.1
Data demonstrate that major decreases in vigorous physical activity occur during grades 9 through 12. This decrease is more profound for girls than for boys, whether the measure is engaging in vigorous physical activity in general or in team sports. The President’s Council on Physical Fitness and Sports concluded that because of the physical health and emotional benefits of physical activity, it should have an increasingly important role in the lives of girls.[17] Adolescents’ interest and participation in physical activity differ by gender.17 Therefore, strategies to increase the amount of physical activity for boys and girls must address these differences and must begin before the disparities in levels of physical activity manifest themselves. Compared to boys, girls are less likely to participate in team sports but more likely to participate in aerobics or dance. Often girls and boys perceive different benefits from physical activity, with boys viewing such activity as competition and girls as weight management. These factors must be considered in developing programs to address the needs of girls. Because boys are more likely than girls to have higher self-esteem and greater physical strength, programs addressing the needs of girls should provide instruction and experiences that increase their confidence and their opportunities to participate in activities, as well as social environments that support involvement in a range of physical activities.17
The Healthy People 2010 objectives offer opportunities to ensure that physical activity and fitness become part of regular healthy behavioral patterns. Encouraging any type or amount of physical activity in leisure time can provide important health benefits, compared to a sedentary lifestyle.
Activities that promote strength and flexibility are important because they may protect against disability, enhance functional independence, and encourage regular physical activity participation. These benefits are particularly important for older people—a good quality of life means being functionally independent and being able to perform the activities of daily living.
Young people are at particular risk for becoming sedentary as they grow older. Therefore, encouraging moderate and vigorous physical activity among youth is important. Because children spend most of their time in school, the type and amount of physical activity encouraged in schools are important components of a fitness program and a healthy lifestyle.
The major barriers most people face when trying to increase physical activity are time, access to convenient facilities, and safe environments in which to be active. Counseling by primary care providers about the need to participate in physical activity also is an important way to change behavior. In addition, facilities need to be accessible to people with disabilities.
(A listing of abbreviations and acronyms used in this publication appears in Appendix H.)
Aerobic: Conditions or processes that occur in the presence of, or requiring, oxygen.[41]
Energy expenditure: The energy cost to the body of physical activity, usually measured in kilocalories.41
Functional independence: The ability to perform successfully and safely activities related to a daily routine with sufficient energy, strength/endurance, flexibility, and coordination.
Physical activity: Bodily movement that is produced by the contraction of skeletal muscle and that substantially increases energy expenditure.1
Moderate physical activity: Activities that use large muscle groups and are at least equivalent to brisk walking. In addition to walking, activities may include swimming, cycling, dancing, gardening and yardwork, and various domestic and occupational activities.
Vigorous physical activity: Rhythmic, repetitive physical activities that use large muscle groups at 70 percent or more of maximum heart rate for age. An exercise heart rate of 70 percent of maximum heart rate for age is about 60 percent of maximal cardiorespiratory capacity and is sufficient for cardiorespiratory conditioning. Maximum heart rate equals roughly 220 beats per minute minus age. Examples of vigorous physical activities include jogging/running, lap swimming, cycling, aerobic dancing, skating, rowing, jumping rope, cross-country skiing, hiking/backpacking, racquet sports, and competitive group sports (for example, soccer and basketball).
Physical fitness: A set of attributes that persons have or achieve that relates to the ability to perform physical activity.1 Performance-related components of fitness include agility, balance, coordination, power, and speed.[42] Health-related components of physical fitness include body composition, cardiorespiratory function, flexibility, and muscular strength/endurance.41
Agility: Ability to start, stop, and move the body quickly and in different directions.
Balance: Ability to maintain a certain posture or to move without falling.
Body composition: The relative amount of body weight that is fat and nonfat.
Cardiorespiratory function: A health-related component of physical fitness that relates to the ability of the circulatory and respiratory systems to supply oxygen during physical activity.
Coordination: Ability to do a task integrating movements of the body and different parts of the body.
Exercise (exercise training): Planned, structured, and repetitive bodily movement done to improve or maintain one or more components of physical fitness.
Flexibility: Ability to move a joint through the full range of motion without discomfort or pain.
Muscular endurance: Ability of the muscle to perform repetitive contractions over a prolonged period of time.
Muscular strength: Ability of the muscle to generate the maximum amount of force.
Power: Ability to exert muscular strength quickly.
Speed: Ability to move the whole body quickly.
Sedentary: Denotes a person who is relatively inactive and has a lifestyle characterized by a lot of sitting.41
[1] U.S. Department of Health and Human Services. Physical Activity and Health: A Report of the Surgeon General. Atlanta, GA: Centers for Disease Control and Prevention (CDC), National Center for Chronic Disease Prevention and Health Promotion, 1996.
[2] Frost, H.; Moffett, J.A.K.; Moser, J.S.; et al. Randomized controlled trial for evaluation of fitness programme for patients with chronic low back pain. British Medical Journal 310:151-154, 1995.
[3] McTiernan, A.; Stanford, J.L.; Weiss, N.S.; et al. Occurrence of breast cancer in relation to recreational exercise in women age 50-64 years. Epidemiology 7(6):598-604, 1996.
[4] Kujala, U.M.; Kaprio, J.; Sarna, S.; et al. Relationship of leisure-time physical activity and mortality: The Finnish twin cohort. Journal of the American Medical Association 279(6):440-444, 1998.
[5] Paffenbarger, R.S.; Hyde, R.T.; Wing, A.L.; et al. The association of changes in physical-activity level and other lifestyle characteristics with mortality among men. New England Journal of Medicine 328(8):538-545, 1993.
[6] Sherman, S.E.; D’Agostino, R.B.; Cobb, J.L.; et al. Physical activity and mortality in women in the Framingham Heart Study. American Heart Journal 128(5):879-884, 1994.
[7] Kaplan, G.A.; Strawbridge, W.J.; Cohen, R.D.; et al. Natural history of leisure-time physical activity and its correlates: Associations with mortality from all causes and cardiovascular disease over 28 years. American Journal of Epidemiology 144(8):793-797, 1996.
[8] Kushi, L.H.; Fee, R.M.; Folsom, A.R.; et al. Physical activity and mortality in postmenopausal women. Journal of the American Medical Association 277:1287-1292, 1997.
[9] Nelson, M.E.; Fiatarone, M.A.; Morganti, C.M.; et al. Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures: A randomized controlled trial. Journal of the American Medical Association 272(24):1909-1914, 1994.
[10] LaCroix, A.Z.; Guralnik, J.M.; Berkman, L.F.; et al. Maintaining mobility in late life. II. Smoking, alcohol consumption, physical activity, and body mass index. American Journal of Epidemiology 137(8):858-869, 1993.
[11] Buchner, D.M. Preserving mobility in older adults. Western Journal of Medicine 167(4):258-264, 1997.
[12] Stenstrom, C.H. Home exercise in rheumatoid arthritis functional class II: Goal setting versus pain attention. Journal of Rheumatology 21(4):627-634, 1994.
[13] CDC. Prevalence of leisure-time physical activity among persons with arthritis and other rheumatic conditions—United States, 1990–91. Morbidity and Mortality Weekly Report 46(18):389-393, 1997.
[14] National Institutes of Health. Optimal calcium intake. In: NIH Consensus Statement 12(4):1-31, 1994.
[15] Snow-Harter, C.; Shaw, J.M.; and Matkin, C.C. Physical activity and risk of osteoporosis. In: Marcus, R.; Feldman, D.; and Kelsey, J., eds. Osteoporosis. San Diego, CA: Academic Press, 1996, 511-528.
[16] Pate, R.R.; Pratt, M.; Blair, S.N.; et al. Physical activity and public health: A recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. Journal of the American Medical Association 273(5):402-407, 1995.
[17] President’s Council on Physical Fitness and Sports. Physical Activity & Sport in the Lives of Girls. Washington, DC: The President’s Council on Physical Fitness and Sports, 1997.
[18] Stofan, J.R.; DiPietro, L.; Davis, D.; et al. Physical activity patterns associated with cardiorespiratory fitness and reduced mortality: The Aerobics Center Longitudinal Study. American Journal of Public Health 88(12):1807-1813, 1998.
[19] Brown, M.; Sinacore, D.R.; and Host, H.H. The relationship of strength to function in the older adult. Journal of Gerontology 50A:55-59, 1995.
[20] Tseng, B.S.; Marsh, D.R.; Hamilton, M.T.; et al. Strength and aerobic training attenuate muscle wasting and improve resistance to the development of disability with aging. Journal of Gerontology 50A:113-119, 1995.
[21] Evans, W.J. Effects of exercise on body composition and functional capacity of the elderly. Journal of Gerontology 50A:147-150, 1995.
[22] Cunningham, D.A.; Paterson, D.H.; Hinmann, J.E.; et al. P.A. Determinants of independence in the elderly. Canadian Journal of Applied Physiology 18(3):243-254, 1993.
[23] Lan, C.; Lai, J.S.; Chen, S.Y; et al. 12-month Tai Chi training in the elderly: Its effect on health fitness. Medicine and Science in Sports and Exercise 30(3):345-351, 1997.
[24] Pate, R.R.; Baranowski, T.; Dowda, M.; et al. Tracking of physical activity in young children. Medicine and Science in Sports and Exercise 28(1):92-96, 1996.
[25] Pate, R.R.; Long, B.J.; and Heath, G. Descriptive epidemiology of physical activity in adolescents. Pediatric Exercise Science 6:434-447, 1994.
[26] CDC. Youth risk behavior surveillance—United States, 1997. Morbidity and Mortality Weekly Report 47(55-3):1-89, 1998.
[27] Anderson, R.E.; Crespo, C.J.; Bartlett, S.J.; et al. Relationship of physical activity and television watching with body weight and level of fatness among children: Results from the Third National Health and Nutrition Examination Survey. Journal of the American Medical Association 279:938-942, 1998.
[28] McKenzie, T.L.; Nader, P.R.; Strikmiller, P.K.; et al. School physical education: Effect of the child and adolescent trial for cardiovascular health. Preventive Medicine 25(4):423-431, 1996.
[29] Sallis, J.F.; McKenzie, T.L.; Alcaraz, J.E.; et al. The effects of a 2-year physical education program (SPARK) on physical activity and fitness in elementary school students. American Journal of Public Health 87(8):1328-1334, 1997.
[30] Sallis, J.F., and Patrick, K. Physical activity guidelines for adolescents: Consensus statement. Pediatric Exercise Science 6:302-314, 1994.
[31] CDC. Guidelines for school and community programs to promote lifelong physical activity among young people. Morbidity and Mortality Weekly Report 46(RR-6):1-36, 1997.
[32] Killen, J.D.; Telch, M.J.; Robinson, T.N.; et al. Cardiovascular disease risk reduction for tenth graders: A multiple-factor school-based approach. Journal of the American Medical Association 260(12):1728-1733, 1988.
[33] Prokhorov, A.V.; Perry, C.L.; Kelder, S.H.; et al. Lifestyle values of adolescents: Results from Minnesota Heart Health Youth Program. Adolescence 28(111):637-647, 1993.
[34] Kelder, S.H.; Perry, C.L.; and Klepp, K.I. Community-wide youth exercise promotion: Long-term outcomes of the Minnesota Heart Health Program and the Class of 1989 study. Journal of School Health 63(5):218-223, 1993.
[35] Arbeit, M.L.; Johnson, C.C.; and Mott, D.S. The Heart Smart Cardiovascular School Health Promotion: Behavior correlates of risk factor change. Preventive Medicine 21(1):18-32, 1992.
[36] Sallis, J.F.; Hovell, M.F.; Hofstetter, C.R.; et al. Distance between homes and exercise facilities related to frequency of exercise among San Diego residents. Public Health Reports 105(2):179-185, 1990.
[37] Carnegie Council on Adolescent Development. A Matter of Time: Risk and Opportunity in the Out-of-School Hours. Recommendations for Strengthening Community Programs for Youth. New York, NY: Carnegie Corporation of New York, 1994.
[38] Cole, G.; Leonard, B.; Hammond, S.; et al. Using “stages of behavioral change” constructs to measure the short-term effects of a worksite-based intervention to increase moderate physical activity. Psychological Reports 82(2):615-618, 1998.
[39] Shephard, R.J. Employee health and fitness—state of the art. Preventive Medicine 12(5):644-653, 1983.
[40] U.S. Department of Transportation (DOT). National Bicycling and Walking Study: Transportation Choices for a Changing America. Pub. FH10A PD 94-023. Washington, DC: DOT, Federal Highway Administration, 1994.
[41] Kent, M. The Oxford Dictionary of Sport’s Science and Medicine. Oxford, England: Oxford University Press, 1994.
[42] Howley, E.T., and Franks, B.O. Health Fitness Instructors Handbook. 3rd ed. Champaign, IL: Human Kinetics, 1997.